


My twin sister's cock

by Jasgirl



Category: Original Work
Genre: Futanari, Other, Twins
Language: English
Status: Completed
Published: 2020-06-05
Updated: 2020-06-05
Packaged: 2021-03-03 20:53:24
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 896
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24561901
Author URL: https://archiveofourown.org/users/Jasgirl/pseuds/Jasgirl
Summary: A twin injects her sister with a drug that makes her grow a cock.
Kudos: 35





	My twin sister's cock

She didn’t want a cock at first.

I had to talk her into it. I had to focus on her need to be different. We were twins, but she’d always liked being just a little different. Standing out. Even when we both decided to get breast implants, she insisted that she needed to be a size larger.

She gave in, eventually, and let me buy the drug. “Just one injection”, I promised her, even though I had bought more than a dozen doses. 

After administering the first injection I held her hand as we both watched her new cock grow in. She was trembling, I squeezed her hand and smiled. “It’ll be alright. You’ll see. You’ll love it, I promise!”

Just to prove it too her, I kneeled between my twin sister’s legs and took her new 4 inch penis between your lips. It was stiff in my mouth, and my sister dug her fingers into my hair as I began to lick and suck. It only took a few moments for her to fill my mouth with hot, gooey cum.

I loved the taste.

The next day I surprised her with another injection. I could see her eyes go wide as I held up the syringe.

“But I thought you said just one...” she said, although I could tell she was excited.

“Don’t you want to be bigger? Think of how good it will feel to have a thick, fat cock. I don’t have one. I know you like to be different. Actually... I’m even a little jealous.” Except I wasn’t jealous at all. I didn’t want a penis for myself. I wanted it for my sister. My beautiful twin sister. 

That night I rode her cock, taking all 8 inches deep inside me. She panted and moaned under me, and came again and again. Filling me full with her cum. After wards I lay on top of her, holding her hand as my sister’s thick, gooey semen oozed out of me.

The next time I didn’t ask. I injected her twice while she slept, and watched her cock throb and grow, crawling across the smooth skin of her stomach as it expanded before my eyes. She didn’t wake up as I took it in your mouth, and I spent nearly an hour leisurely enjoying my sister’s 17 inch cock before she finally came.

She wasn’t angry. She couldn’t be angry. All she could do was pant and groan as I stroked her enormous cock, making her cum again and again.

Later, as we lay in bed together, she looked at me. Her eyes were half lidded, both our bodies sticky with her cum. “Why... why did you...?” 

“You belong to me.” I began stroking her cock again, and she closed her eyes and gave in to the pleasure.

“I love you, and now you’re mine forever.”

Two more injections the next day. Half of the entire stash. She didn’t resist. She didn’t say anything at all. My sister had discovered that she could easily take the head of her cock in her mouth. When I woke up I found her sucking, eyes closed, a look of bliss on her cum plastered face. Now I watched as her cock began to grow again, thickening, stretching her mouth wide. Her eyes opened in surprise as her growing penis started to push down her throat. I helped her pull it out, and she lay back panting as it grew in my arms.

28 inches. My twin sister’s cock was a thick trunk, throbbing as it lay across her stomach and chest, the fat, drooling head resting over her shoulder.

She looked up at me as I kneeled next to her on the bed, my hands slowly stroking her. “Ssss...sister.... uhhhhh” The drug had begun to overwhelm her mind. A common side effect. I didn’t care. I liked her like this.

My hand caressed her cum covered cheek. “Shhh.... its okay. I love you. I’ll make sure you feel good, forever.” I guided the tip of her gigantic cock back toward her mouth, and smiled as she closed her eyes and began to eagerly suck. 

I joined her, laying next to my twin sister, rubbing my body against her mammoth cock, grinding against the hot, throbbing flesh. When she came we shared her cum. I licked it from her chin as she kept sucking. My sister was greedy, and her cock didn’t leave her mouth, even as she drifted off to sleep. But that was fine.

I wanted my sister to love her cock. I wanted her to love swallowing her own cum. I wanted her to be mine. My toy. My lover forever, trapped by her lust, her mind too soft from arousal, drugs and her growing cock to ever leave our bed again.

I smiled as I climbed on top of my twin sister, leaning down brush her hair from her sleeping face. She looked so beautiful with her massive cock crammed into her mouth, but I knew she’d be even sexier once it was so much bigger.

I pulled the cap off two more syringed and injected them directly into her cock, and then closed my eyes and leaned back, letting out a gasp as my sisters’ growing dick throbbed against my pussy.

She was going to be enormous.

And she belonged to me.


End file.
